Viewing the compare page on a public repository as an anonymous user shows errors

Summary

When visiting the "Compare Branches" page as an anonymous user on a publicly accessible repository, error dialogs are shown.

Steps to Reproduce

1. Enable public access on a repository
2. Open an "Incognito" window in your browser
3. Visit the compare page for the repository

Expected Results

I can view the compare page.

Actual Results

I can view the compare page after closing error dialogs.

Workaround

Authenticate as a user.